1. Field of the Invention
The present invention relates in general to computing systems, and more particularly to, systems for managing destage scan times in a cache.
2. Description of the Related Art
One goal of computer storage systems is to reduce the number of destage conflicts when destaging storage tracks from a write cache so that the storage system operates more efficiently and/or faster. A destage conflict can occur when a storage track is being destaged from the write cache while a host is trying to write data to the storage track. This situation may be created because contemporary storage systems typically destage storage tracks shortly after the storage track is written to and the host must wait until the storage track is destaged from the write cache before the host is able to again write to the storage track. One technique to reduce the number of destage conflicts includes keeping storage tracks in the write cache for a longer period of time before destaging the storage tracks so that a storage track may be written to multiple times before the storage track is destaged. While this is an effective technique for reducing destage conflicts, it is also desirable that storage tracks not reside in the write cache too long so that the cache becomes completely full. It is also desirable that the cache not experience an undue amount of fluctuating between being nearly full and being nearly empty, which is known as oscillation.